blob: acb77a9a4e4797db2fa0a99a4e0f111839bdb56f (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
|
aarch-64 emulation much slower since release 8.1.5 (issue also present on 8.2.1)
Description of problem:
Since QEMU 8.1.5 our aarch64 based emulation got much slower. We use a linux 5.4 kernel which we cross-compile with the ARM toolchain. Things that are noticable:
- Boot time got a lot longer
- All memory accesses seem to take 3x longer (can be verified by e.g. executing below script, address does not matter):
```
date
for i in $(seq 0 1000); do
devmem 0x200000000 2>/dev/null
done
date
```
Steps to reproduce:
Just boot an ARM based kernel on the virt machine and execute above script.
Additional information:
I've tried reproducing the issue on the master branch. There the issue is not present. It only seems to be present on releases 8.1.5 and 8.2.1.
I've narrowed the problem down to following commit on the 8.2 branch (@bonzini): ef74024b76bf285e247add8538c11cb3c7399a1a accel/tcg: Revert mapping of PCREL translation block to multiple virtual addresses.
Let me know if any other information / tests are required.
|